Leaf Surface Research Articles

Local and landscape predictors of herbivory on subsistence croplands in Brazilian dry forests

ABSTRACT Understanding the impact of herbivores on croplands is critical to developing sustainable agricultural landscapes. Here, we test the hypothesis that field size and landscape structure modulate the levels of herbivory in cowpea and maize subsistence croplands in Brazilian drylands. We conducted the study in nine small-scale farms with varying levels of landscape structure and field sizes (0.10–1.67 ha). In each farm, we haphazardly sampled 20 plants of maize and cowpea. The frequency of foliar herbivory was high for both crops (0.45–0.72), but the average magnitude of damage was low (<3% of leaf surface in both crops), indicating that herbivory is not an ecosystem disservice. Nonetheless, the field size and level of human impact on the landscape matrix were positively related to the frequency and magnitude of damage on maize foliage and cowpea foliage and pods. Landscape composition (proportion of woodland/forest surrounding the field) and configuration (number of surrounding woodland/forest patches) had weaker effects on herbivory levels, mixing positive and negative effects on both crops. Our findings indicate that herbivory attack is not concerning in the agricultural fields studied, but suggest that maize and cowpea should be preferably grown in small fields surrounded by an environmental-friendly matrix and patches of conserved ecosystems.

β-Cyclodextrin-optimized supramolecular nanovesicles enhance the droplet/foliage interface interactions and inhibition of succinate dehydrogenase (SDH) for efficient treatment of fungal diseases

BackgroundPlant fungal diseases present a major challenge to global agricultural production. Despite extensive efforts to develop fungicides, particularly succinate dehydrogenase inhibitors (SDHIs), their effectiveness is often limited by poor retention of fungicide droplets on hydrophobic leaves. The off-target losses and unintended release cause fungal resistance and severe environmental pollution.ResultsTo update the structure of existing SDHIs and synchronously realize the efficient utilization, we have employed a sophisticated supramolecular strategy to optimize a structurally novel SDH inhibitor (AoH25), creating an innovative supramolecular SDH fungicide (AoH25@β-CD), driven by the host-guest recognition principle between AoH25 and β-cyclodextrin (β-CD). Intriguingly, AoH25@β-CD self-assembles into biocompatible supramolecular nanovesicles, which reinforce the droplet/foliage (liquid-solid) interface interaction and the effective wetting and retention on leaf surfaces, setting the foundation for enhancing fungicide utilization. Mechanistic studies revealed that AoH25@β-CD exhibited significantly higher inhibition of SDH (IC50 = 1.56 µM) compared to fluopyram (IC50 = 244.41 µM) and AoH25 alone (IC50 = 2.29 µM). Additionally, AoH25@β-CD increased the permeability of cell membranes in Botryosphaeria dothidea, facilitating better penetration of active ingredients into pathogenic cells. Further experimental outcomes confirmed that AoH25@β-CD was 88.5% effective against kiwifruit soft rot at a low-dose of 100 µg mL-1, outperforming commercial fungicides such as fluopyram (52.4%) and azoxystrobin (65.4%). Moreover, AoH25@β-CD showed broad-spectrum bioactivity against oilseed rape sclerotinia, achieving an efficacy of 87.2%, outstripping those of fluopyram (48.7%) and azoxystrobin (76.7%).ConclusionThis innovative approach addresses key challenges related to fungicide deposition and resistance, improving the bioavailability of agricultural chemicals. The findings highlight AoH25@β-CD as a novel supramolecular SDH inhibitor, demonstrating its potential as an efficient and sustainable solution for plant disease management.Graphical

NaCl-induced effects on photosynthesis, ion relations, and growth of Chloris gayana Kunth in the presence of two levels of KCl

Soil salinization is a widespread environmental problem that impacts agriculture. Potassium fertilization is often associated with stress mitigation. Aiming to identify the ability of Rhodes grass (Chloris gayana Kunth) to cope with high salt as well as to investigate the potential of K+ fertilization to alleviate stress symptoms, we investigated the combined effects of NaCl and KCl on photosynthesis, ion distribution, and growth of two Rhodes grass cultivars, Callide and Reclaimer. Plants were grown under different regimes (0, 200, 400, and 600 mM NaCl + 1 or 10 mM KCl). For Reclaimer, 10 mM KCl induced positive effects in photochemistry under 0 and 200 mM NaCl, as illustrated by fluorescence transients OJIP-bands and JIP-test parameters. However, such improvements did not lead to superior biomass accumulation nor net photosynthesis compared to the corresponding treatments under 1 mM KCl, which may not justify KCl application. In Callide 10 mM KCl induced deleterious effects on photochemistry of plants under low NaCl levels. High salinity (600 mM) induced stress-triggered biomass reduction of up to 70% in both cultivars, but all plants remained photosynthetically active. Exposure of both cultivars to NaCl concentrations equal to or higher than 200 mM triggered response mechanisms such as the ability to accumulate inorganic solutes accounting to osmotic potential, stomata closure, and excretion (up to 70%) of the retained Na+ onto the leaf surface irrespective of KCl. Our data reinforce that Rhodes grass is an auspicious forage crop for saline environments and, therefore, in revegetation programs for saline soils pasture in subtropical regions.

Exceptional anisotropic superhydrophobicity of sword-lily striated leaf surface and soft lithographic biomimicking using polystyrene replica

Herein, we report unusually high anisotropic superhydrophobicity, unidirectional self-cleaning, and biomimicking of adaxial sword-lily (Gladiolus hortulanus) leaf comprising three distinct levels of surface textures. Observably, the static anisotropic wetting and rolling of water droplets are more favourable in the parallel (or, striation) direction than in the perpendicular direction. Inspired from such water repellency of the sword lily leaf surface, here bio-mimicked polystyrene (PS) leaf construct is developed through a soft lithographic technique. Considering different water droplet sizes (4–10 μl) on natural lily leaf and bio-mimicked PS construct surfaces, the respective parallel (θ ||) and perpendicular (θ ⊥) water contact angles (WCAs) stand at, θ || ∼143°–147°, θ ⊥ ∼156°–169°; and θ || ∼130°–139°, θ ⊥ ∼142°–145°. Moreover, the specimens under study exhibit roll-off angles ranging, α || ∼8°–23° (α ⊥ ∼16°–41°) and α || ∼21°–49° (α ⊥ ∼40°–55°) along parallel (and perpendicular) directions; respectively. A noticeable difference in α ⊥ and α || values can be ascribed to the profound three-phase contact line (TCL) pinning along the perpendicular direction taking advantage of striation as means of barrier. The roll-off angles can also alter due to a variation in the droplet volume. The unusual anisotropic superhydrophobicity and unidirectional droplet roll-off can be attributed to the entrapped air within the micro-nano texture beneath the water droplet along with the pinning effect in the perpendicular direction caused by the striated heights.

First Report of Powdery mildew Caused by Golovinomyces ambrosiae on Verbena × hybrida in the U.S.

Verbena × hybrida, also known as common garden verbena, has an important ornamental value for their wide range of flower colors and for attracting hummingbirds and butterflies. During the winter of 2021-2022 (December through February), more than 50% pot-grown verbena plants showed symptoms of powdery mildew in a field trial at a Syngenta Crop Protection research facility in Vero Beach, FL. Symptoms were characterized by the development of white, superficial mycelium on the adaxial side of leaves which, eventually, progressed to covering the whole surface of leaves, causing leaf discoloration, shoot distortion, and eventual plant death. Morphological characterization was carried out by observing powdery mildew colonies under the microscope. This powdery mildew forms dense patches of white mycelia, mainly on the adaxial leaf surfaces. The mycelium was a mat of hyphae with septa. Conidiophores were erect. The foot cells were straight, followed by one to three short cells bearing short chains of up to four conidia. The conidia were hyaline and ellipsoidal to doliiform in shape. Conidial germination is of the Eudoidium type. The conidia ranged from 25 to 32 μm long by 12 to 16 μm wide. The length to width ratio ranged between 1.6 and 2.3, but most were between 2.0 and 2.2. This is further verification of its identity as Golovinomyces ambrosiae and not Golovinomyces latisporus, because the length to width ratio of the latter species is consistently less than 2.0 (Qiu et al. 2020). Chasmothecia were not observed. Additionally, the ITS, GAPDH, and IGS regions were sequenced using the primer pairs ITS4/ITS5 (White et al. 1990), PMGAPDH1/PMGAPDH3R (Bradshaw et al. 2022a), and IGS-12a/NS1R (Carbone and Kohn 1999), respectively. The ITS region (GenBank number=PP924119) cannot distinguish between G. latisporus and G. ambrosiae and as such aligned 100% with both species on GenBank. However, the GAPDH and IGS regions can be used to distinguish G. ambrosiae from G. latisporus (Bradshaw et al. 2022b). The GAPDH (GenBank number=PP931995) and IGS (GenBank number=PP931996) regions aligned 100% with multiple G. ambrosiae sequences from GenBank including ON360708 and MK452567, respectively. The specimen was deposited in the Larry F. Grand Mycological Herbarium (NCSLG 24479). To confirm pathogenicity, 'Tuscany® Pink Picotee' and 'Quartz XP Violet with Eye' plugs were transplanted to 10-cm diameter pots containing ProMix potting mix and maintained in a greenhouse (± 26 °C). Inoculation was carried out 21 days after transplanting by touching infected leaves onto healthy leaves of 15 disease-free plants of each variety. Fifteen non-inoculated plants of each variety were used as controls. Typical powdery mildew symptoms and signs were first observed ten days after inoculation and the pathogen was more aggressive on 'Tuscany® Pink Picotee'. Symptoms were not observed on non-inoculated plants. The fungus was morphologically identical to the one originally recovered from infected plants in the field. There have been many reports of Golovinomyces spp. affecting Verbena spp. worldwide; however, this is the first report of G. ambrosiae causing powdery mildew on Verbena × hybrida in the U.S. (Braun and Cook, 2012, Choi et al., 2021; Bradshaw et al. 2024). Powdery mildews reduce plant quality and decreases the aesthetics value of infected plants, causing great losses to the ornamental industry. Correct identification of the causal agent is crucial to recommend appropriate control methods, as they may differ according to the pathogen species.

Downsizing gum Arabic-based abamectin particles using flash nanoprecipitation method for enhanced pesticide deposition

Pesticides are vital for ensuring crop protection and stable yields, but their low efficiency and eco-unfriendly carriers raise environmental concerns. In this study, abamectin nanopesticides were designed and fabricated using natural polysaccharides [gum arabic (GA)] and a co-stabiliser via flash nanoprecipitation (FNP) method to reduce the size of nanopesticides and enhance their foliar affinity and deposition. Various co-stabilisers were innovatively introduced into the FNP process; the synergy between GA and the co-stabiliser significantly reduced the particle size (111.5 nm), narrowed the size distribution (polydispersity index = 0.078), and enhanced the stability and release performance of the nanopesticides. Importantly, the downsized nanopesticides effectively improved retention on leaf surfaces, reducing pesticide loss. In addition, because of the excellent control capability of the FNP method, the particle size of the nanopesticides could be flexibly adjusted by modifying the flow-based process parameters. Nanopesticides with small sizes demonstrated good control efficacy against Tetranychus urticae, comparable to those of commercial emulsion in water formulations. This study provides an effective approach for enhancing the utilisation efficiency of pesticide droplets by reducing particle size to ensure sustainable agriculture.

Effects of Different Shade Treatments on the Epidermal Wax Deposition of Hosta Genotypes with Different Glaucousness of Leaf Surface

Epidermal wax is strategically situated at the interface between plants and air; therefore, it plays a key role in plants’ interactions with their surroundings. It is also unstable and susceptible to light intensity. Hosta plants are shade-loving herbs with admirable flowers and leaves. Hosta ‘Halcyon’ and Hosta ensata F. Maek. are two species of Hosta with a glaucous and a glossy appearance, respectively. Light intensity can affect the composition of epicuticular wax on the leaf surface, which influences the leaf color phenotype and ornamental value. In this paper, the crystal micromorphology, content, and components of epicuticular wax on the leaves of two species of Hosta under different light conditions (10%-, 30%-, 50%-, 70%-, and 100%-intensity sunlight, relative light intensity (RLI)) have been studied using pot experiments. The results indicate that the epicuticular wax crystals of H. ‘Halcyon’ and H. ensata are tubular and platelet-like, respectively. The wax crystals of H. ‘Halcyon’ melted and formed a thick crust under 100% RLI, and those of H. ensata melted and formed a thick crust under 70% and 100% RLI conditions. The primary ingredients of the epicuticular wax of the two species of Hosta contained primary alcohols, alkanes, fatty acids, and esters; β-diketones were only detected in H. ‘Halcyon’. The quantity of epicuticular wax of H. ‘Halcyon’ reduced at first and then increased with an RLI increase, achieving its lowest value at 50% RLI, but that of H. ensata declined little by little. The amounts of C28 primary alcohols, C31 alkanes, and C18 fatty acids were significantly higher than those of other carbon atoms in the two genotypes of Hosta. The C31β-diketones content decreased with the increase in light intensity, which caused the white frost phenotype to gradually weaken in H. ‘Halcyon’.

First Report of Klebsiella variicola Causing Tomato Pith Necrosis in Yunnan Province, China.

Tomato (Solanum lycopersicum L.) is a key vegetable crop in China. In August 2023, an outbreak of bacterial pith necrosis in tomato occurred in Lufeng County, Yunnan Province, China, affecting over 40% of the tomato plants in a greenhouse. The stems of infected plants developed a waterlogged soft rot and the disease progressed, the lower leaves and lateral branches of infected plants gradually wilted and died. A longitudinal cut of the stem revealed hollow pith with brown vascular tissue. To isolate the pathogen, the plant surface was disinfested with 75% ethanol. Then, a piece of infected tissue from the base of the stem was excised and immersed in sterile water for 2 min. A small amount of liquid was streaked onto TTC (2,3,5-triphenyltetrazolium chloride) agar medium using an inoculation loop, and plates were incubated at 28℃ for 24 h. Colonies on the TTC plate were white, indicating that the pathogen was not Ralstonia solanacearum. Colonies grown on LB (Luria-Bertani) agar medium were randomly selected and subjected to preliminary pathogenicity tests. Based on the results, a colony named Kv4 was selected and purified through six subcultures in LB agar medium. Biochemical tests showed the strain utilized D-sorbitol, raffinose and citrate but not adonitol, and was positive for methyl red, D-glucose (acid), urea hydrolysis, lysine decarboxylase, and motility, and negative for phenylalanine deaminase, H2S production, indole production, and ornithine decarboxylase. These characteristics align with Klebsiella species (Garrity et al. 2007). To determine the species of strain Kv4, partial sequences of the 16S rDNA, phoE, leuS, and rpoB genes were amplified (Barrios-Camacho et al. 2019) and sequenced. Through BLASTn analysis, strain Kv4 sequences of 16S rDNA (OR888750) had 99.47% identity (1488/1496 bp), phoE (OR899599) had 98.69% (605/613 bp) identity, leuS (OR899598) had 99.07% identity (959/968 bp), and rpoB (OR899597) had 97.69% (633/648 bp) identity with Klebsiella variicola strain FF0907. Using the ClustalW algorithm in MEGA11 for nucleotide sequence alignment, phylogenetic trees were constructed with 16S and phoE, leuS, and rpoB via the neighbor-joining method, confirming strain Kv4 as K. variicola. To test pathogenicity, the roots of 25 'Moneymaker' tomato plants with four to five true leaves were wounded, then each plant inoculated with a 15 mL bacterial suspension (OD600=0.6) of strain Kv4, while the control plants received sterile water. Plants were incubated at 28℃ with a 16 h photoperiod. Experiments were done twice. At 15 days after inoculation (DAI), all plants inoculated with Kv4 showed yellowing, unevenly distributed small black necrotic spots on the leaf surface, and purple-brown soft rot at the stem base. By 18 DAI, there was a gradual transformation of the stem bases from green to purplish brown. At 21 DAI, 60% of the inoculated plants displayed brownish soft rot at the stem base. In contrast, the control plants remained symptom-free. The pathogen was re-isolated from the stem and identified as K. variicola via sequence analysis of 16S, phoE, leuS, and rpoB. In recent years, several new bacterial pith necrosis diseases were reported in tomato (Guo et al. 2023; Ivić et al. 2023). This is the first study documenting K. variicola causing bacterial pith necrosis in tomato. Once considered a benign plant endophyte, Sun et al. (2023) reported K. variicola causing banana sheath rot in Guangdong and Guangxi Provinces, China. Malik et al. (2023) reported that K. variicola caused leaf streak in sorghum in India. This report of bacterial pith necrosis in tomato caused by K. variicola strain Kv4 underscores the escalating threat posed by emerging pathogens to agricultural production. The emergence of K. variicola as a tomato pathogen complicates plant disease management strategies.

First Report of Powdery Mildew on Vitis bryoniifolia Caused by Erysiphe necator in China.

Grapes, belonging to the genus Vitis, are one of the world's most economically valuable fruit crops, which are widely used as the source of wine, raisins, and juice. The genus Vitis contains about 60 species mainly distributed in Asia, Europe, and North America to northern South America (Wan et al. 2013). In May 2022, severe powdery mildew symptoms were found on wild Vitis bryoniifolia plants at Guizhou Normal University, Guiyang, China. The incidence observed was approximately 85% among 50 V. bryoniifolia plants. Infected leaves appear white powdery patches, eventually leading to chlorosis to necrosis. Mycelia occurred on adaxial and abaxial leaf surfaces, petioles and young shoots. Upon microscopic observation hyphae were hyaline and 3.5-6 μm wide. Hyphal appressoria were solitary and lobed to multilobed. Conidiophores were erect, straight to somewhat flexuous and 80-130 µm long (n = 30). Foot cells were subcylindrical to curved-sinuous at the base, followed by 2-4 cells. Conidia formed singly (occasionally 2-6 in a chain) and were ellipsoid to ovoid in shape with dimensions of 22.5-38 × 12-19.5 µm (n = 50). No fibrosin bodies were observed on conidia. Based on these morphological characteristics, the powdery mildew fungus strongly resembled Erysiphe necator (Braun and Takamasu 2000; Zheng et al. 1987) that has been shown to cause powdery mildew on Vitis (Gadoury et al. 2012; Gaforio et al. 2011; Qiu et al. 2015). To confirm the identification, the ribosomal DNA internal transcribed spacer (ITS) and the ribosomal large subunit (LSU) region were amplified and sequenced using the ITS1/ITS4 primer pair (White et al. 1990) and the NL1/NL4 primer pair (Ziemiecki et al. 1990), respectively. The spliced 1250-bp ITS-LSU sequence (GenBank accession no. PP188565) shared 99.84-100% identity with ITS-LSU sequences of E. necator (LC028995, LC028996, ON073862, LC777882, and OM033353). Based on the phylogenetic analysis of the combined ITS-LSU dataset of Erysiphe species (Takamasu et al. 2015), PP188565 was grouped in a clade with E. necator strains MUMH530, MUMHs141, and VPRI19719. To perform pathogenicity analysis, leaves of three healthy, potted 1-year-old V. bryoniifolia plants were inoculated by gently pressing with diseased leaves. Three non-inoculated healthy plants served as controls. All plants were incubated in a greenhouse at 25 ± 2°C with 80% relative humidity. Powdery mildew symptoms, similar to field conditions were observed on inoculated plants 13 days after inoculation, whereas control plants remained symptomless. Fungus reisolated from inoculated V. bryoniifolia plants was morphologically identical to that on originally diseased plants, and the spliced ITS-LSU sequence of reisolated fungus shared 100% identity with PP188565, fulfilling Koch's postulates. Based on the morphological and molecular characterizations, the powdery mildew fungus was identified as E. necator. To our knowledge, this is the first report of powdery mildew caused by E. necator on V. bryoniifolia in China. This work further expands the host range of Erysiphe necator on Vitis species.

The leaf surface micromorphology of plants obtained from crosses between Elymus farctus and the stable form × Trititrigia cziczinii × wheat cultivar ‘Botanicheskaya 3’

The leaf surface micromorphology of plants obtained from crosses between Elymus farctus and the stable form × Trititrigia cziczinii × wheat cultivar ‘Botanicheskaya 3’

Productivity of Certain Varieties of Apples and Importance of Their Gene Formation

Due to the diversity of its natural and historical conditions, Azerbaijan is one of the centers of the initial formation of many plants, having a great genetic richness of the plant world. A large number of valuable varieties and forms of food and agricultural plants have been created through folk selection and scientific selection, with the history of agriculture covering several millennia. However, massive and anthropogenic disturbances of all these natural and cultural heritage ecosystems, which are the irreplaceable wealth of the people, created a large number of valuable varieties and forms of ecological and agricultural plants. However, all this natural and cultural heritage, which is the irreplaceable wealth of the people, is threatened with destruction as a result of mass and anthropogenic disturbances of ecosystems, ecological and agricultural changes, and the wide application of modern breeding achievements. In addition to all this, the study, protection, and effective use of the gene pool of the apple plant in the country is one of the main factors. In this regard, based on our long-term research, with the efficient use of the gene pool of the apple plant in Azerbaijan, new “spur”-type selection varieties (Nigar, Ziya, Zirva, Marfa, Sulh, Gobustan, Zumrud, Kyzyld Taj, Khazar, Eldar, Ulvi, Nübar, Vatan, Makhmari, Nuran, Sarvan, Chiraggala, Davamli, Emil, Elvin, Paizliq Guba, Zizliq Guba, Shabran, Sadaf and Sevinj) were created by us. In the article, the parental pairs of those cultivars are reflected in the ripening period, ripening, fruiting periods, tree parameters (height, diameter of the umbel, circumference of the stem), productivity indicators, leaf surface, infection rates of scab disease, average mass of fruits and tasting prices. At the same time, the article contains the introduction, research conditions, methodology, material, results, discussion, recommendations, and used literature sources.

Cell-type specific localization and biological activity of the volatiles from the endemic species Chaerophyllum coloratum L.

Main conclusionNew findings are presented for Chaerophyllum coloratum L. on the volatile composition of the essential oil, based on data of hydrosol and fresh plant material, light and electron microscopy of leaves, and cytotoxic and antiviral activity.The widespread Apiaceae family includes many well-known and economically important plants that are cultivated as food or spices. Many produce essential oils and are generally a source of secondary metabolites and compounds that have numerous applications in daily life. In this study, the chemical composition of volatile organic compounds (VOCs), ultrastructure and biological activity of the Mediterranean endemic species Cheaerophyllum coloratum L. are investigated, as literature data for this plant species are generally very scarce. The essential oil and hydrosol were extracted from the air-dried leaves by hydrodistillation and the chemical composition of both extracts was analysed by GC–MS in conjunction with headspace solid-phase microextraction (HS-SPME) of VOCs from the hydrosol and the fresh plant material. In the composition of the essential oil, the oxygenated sesquiterpenes spathulenol and caryophyllene oxide were the most abundant components. In the fresh plant material, non-oxygenated sesquiterpenes dominated, with β-caryophyllene and germacrene D being the main components. The hydrosol was dominated by monoterpenes, with the oxygenated monoterpene p-cymen-8-ol being the most abundant. Light and electron micrographs of the leaf of C. coloratum show secretory structures, and we hypothesize that glandular leaf trichomes, secretory epidermal cells and secretory canals are involved in the production of volatiles and their secretion on the leaf surface. Since the biological potential of C. coloratum is poorly investigated, we tested its cytotoxic activity on cancer and healthy cell lines and its antiviral activity on plants infected with tobacco mosiac virus (TMV). Our results dealing with the composition, ultrastructure and biological activity show that C. coloratum represent a hidden valuable plant species with a potential for future research.

Influence of air dust on anatomo-morphological and biochemical parameters of Plantago Major L

Pollution has a great impact on the environment. Plants being the representatives of autotrophic organisms are the first to face it. The photosynthesis suppression, water exchange violation, transpiration reduction, growth general oppression and plants’ development are exposed to pollutants. This causes changes in leaf coloration, necroses, premature leaf fall, changes in growth form. The effect of air dust on anatomo-morphological parameters of plantain and the effect of dust pollution on plantain’s (Plantago major L.) production processes have been studied, the dust-holding capacity of plantain leaves has been estimated. The correlation between the dust pollution level and the stomata density in the leaves’ epidermis of model species has been found out. Mass of aboveground organs (g) and leaf lamina area (cm2), the number of stomata on the leaf surface (pcs./mm2), the dust accumulation level on the leaf surface (g) have been analyzed in model species. Weighing was carried out with an accuracy of 0.001 g on electronic scales. According to the performed analysis, we have come to the conclusions: species of the plantain have 10 to 50 mg of dust particles deposited on the leaf surface, the size of leaf plates and the mass of plantain's terrestrial organs decrease as the level of air pollution increases. It should be underlined that air pollution causes an increase in the density of stomata in plantain associated with a reduction in the area of the assimilating apparatus and it can be viewed as one of the compensatory mechanisms.

Fostering rehydration and facilitating bioactive release through cellulose-assisted leaf surface treatment

Glyphosate is a widely used herbicide in weed control and crop protection. However, its low bioavailability on leaf surfaces of weeds led to excessive use of glyphosate, inducing herbicide-resistant development and major sustainable agricultural and environmental concerns. This study addresses these challenges by developing cellulose-assisted glyphosate formulations using superior rehydration and sustainable release capability of nanocelluloses. We prepared glyphosate-loaded nanocellulose particles (CNP) and cellulose nanofibers (CNF) to enhance the rehydration and sustained release of glyphosate on leaf surfaces. Our results have demonstrated that nanocelluloses significantly improved water capture on the leaf surface and gradual release of glyphosate, with CNP and CNF formulations showing an 8.75-fold increase in water adsorption on cotton leaves compared to the control group over 12 h. Furthermore, incorporating an inorganic salt improved moisture adsorption efficiency. The formulations exhibited high compatibility with existing spray technologies, offering substantial economic and environmental benefits for agriculture practices. This approach highlights the potential application of polysaccharides in revolutionizing agrochemical applications and environmental sustainability, providing great potential in agricultural spraying practices.

Biocompatible Nano-Cocrystal Engineering for Targeted Herbicide Delivery: Enhancing Efficacy through Stimuli-Responsive Release and Reduced Environmental Losses.

In addressing the critical challenges posed by the misuse and inefficiency of traditional pesticides, we introduce a Nano-Cocrystal material composed of the herbicide clopyralid and coformer phenazine. Developed through synergistic supramolecular self-assembly and mechanochemical nanotechnology, this Nano-Cocrystal significantly enhances pesticide performance. It exhibits a marked improvement in stability, with reductions in hygroscopicity and volatility by approximately 38%. Moreover, it intelligently modulates release according to environmental factors, such as temperature, pH, and soil inorganic salts, demonstrating decreased solubility by up to four times and improved wettability and adhesion on leaf surfaces. Importantly, the herbicidal activity surpasses that of pure clopyralid, increasing suppression rates of Medicago sativa L. and Oxalis corniculata L. by up to 27% at the highest dosage. This Nano-Cocrystal also shows enhanced crop safety and reduced genotoxicity compared to conventional formulations. Offering a blend of simplicity, cost-effectiveness, and robust stability, our findings contribute a sustainable solution to agricultural practices, favoring the safety of nontarget organisms.

Plant-Leaf Recognition Based on Sample Standardization and Transfer Learning

In recent years, deep-learning methods have significantly improved the classification results in the field of plant-leaf recognition. However, limited by the model input, the original image needs to be compressed to a certain size before it can be input into the convolutional neural network. This results in great changes in the shape and texture information of some samples, thus affecting the classification accuracy of the model to a certain extent. Therefore, a minimum enclosing quadrate (MEQ) method is proposed to standardize the sample datasets. First, the minimum enclosing rectangle (MER) of the leaf is obtained in the original image, and the target area is clipped. Then, the minimum enclosing quadrate of the leaf is obtained by extending the short side of the rectangle. Finally, the sample is compressed to fit the input requirements of the model. In addition, in order to further improve the classification accuracy of plant-leaf recognition, an EC-ResNet50 model based on transfer-learning strategy is proposed and further combined with the MEQ method. The Swedish leaf, Flavia leaf, and MEW2012 leaf datasets are used to test the performance of the proposed methods, respectively. The experimental results show that using the MEQ method to standardize datasets can significantly improve the classification accuracy of neural networks. The Grad-CAM visual analysis reveals that the convolutional neural network exhibits a higher degree of attention towards the leaf surface features and utilizes more comprehensive feature regions during recognition of the leaf samples processed by MEQ method. In addition, the proposed MEQ + EC-ResNet50 method also achieved the best classification results among all the compared methods. This experiment provides a widely applicable sample standardization method for leaf recognition research, which can avoid the problem of sample deformation caused by compression processing and reduce the interference of redundant information in the image to the classification results to a certain degree.

Taxonomic relevance of leaf surface micromorphology in Korean Clematis L. (Ranunculaceae).

Clematis, one of the largest genera of the family Ranunculaceae, has a wide array of morphological variation and is considered the most difficult group of taxa in terms of infrageneric discrimination. This study assessed the leaf micromorphological features of 19 Clematis taxa (16 species and three varieties) found in Korea. The leaf surface features were studied under scanning electron microscopy, and the stomatal counting and measurement were carried out under light microscopy. Clematis are hypostomatic, meaning the stomata are only found on the abaxial surface of the leaf. Observed taxa showed near uniformity in the epidermal cell type, structure, and morphology on both surfaces of the leaf. Differences were observed in the presence and absence and/or abundance of trichomes on both the adaxial and abaxial surfaces, the epidermal cell boundary, and the periclinal and anticlinal wall of the cells. Differences were also observed in the number of the epidermal cells connected with the stomata on the abaxial surface, with small differences noted in epidermal cell shapes. The ANOVA showed a significant variation in the stomata density in the studied taxa (P < 0.0001). The cluster analysis based on 13 leaf micromorphological features generated four major clusters. These results indicated similarities in certain key leaf micromorphological features among taxa from the Tubulosae, Clematis, and Virona sections. In the genus Clematis, as with other morphological characteristics, using leaf micromorphological characters alone, which possess limited taxonomic value, proves inadequate for resolving infrageneric relationships. However, incorporating certain features with other morphological characteristics offers a possible alternative means of determining the infrageneric relationships within the genus.

Nanoparticle LDH enhances RNAi efficiency of dsRNA in piercing-sucking pests by promoting dsRNA stability and transport in plants

Piercing-sucking pests are the most notorious group of pests for global agriculture. RNAi-mediated crop protection by foliar application is a promising approach in field trials. However, the effect of this approach on piercing-sucking pests is far from satisfactory due to the limited uptake and transport of double strand RNA (dsRNA) in plants. Therefore, there is an urgent need for more feasible and biocompatible dsRNA delivery approaches to better control piercing-sucking pests. Here, we report that foliar application of layered double hydroxide (LDH)-loaded dsRNA can effectively disrupt Panonychus citri at multiple developmental stages. MgAl-LDH-dsRNA targeting Chitinase (Chit) gene significantly promoted the RNAi efficiency and then increased the mortality of P. citri nymphs by enhancing dsRNA stability in gut, promoting the adhesion of dsRNA onto leaf surface, facilitating dsRNA internalization into leaf cells, and delivering dsRNA from the stem to the leaf via the vascular system of pomelo plants. Finally, this delivery pathway based on other metal elements such as iron (MgFe-LDH) was also found to significantly improve the protection against P. citri and the nymphs or larvae of Diaphorina citri and Aphis gossypii, two other important piercing-sucking hemipeteran pests, indicating the universality of nanoparticles LDH in promoting the RNAi efficiency and mortality of piercing-sucking pests. Collectively, this study provides insights into the synergistic mechanism for nano-dsRNA systemic translocation in plants, and proposes a potential eco-friendly control strategy for piercing-sucking pests.Graphical

Enhanced Tobacco Yield Prediction Using Spatial Information and Exogenous Variable-driven Machine Learning Models

Remote sensing technology has been essential in studying the relationship between tobacco canopy spectral characteristics and biomass yield. This study has been conducted in Garnepudi, Andhra Pradesh, employed satellite imagery obtained between 2015 and 2023 to extract vegetation indices (VI’s). Accurately predicting yield is crucial for India's economy. This study investigates the efficacy of various predictive models for tobacco yield forecasting using multiple vegetation indices: Normalized Difference Vegetation Index (NDVI), Green Normalized Difference Vegetation Index (GNDVI), Soil Adjusted Vegetation Index (SAVI), Modified Soil Adjusted Vegetation Index (MSAVI), Leaf Area Index (LAI) and Leaf Surface Water Index (LSWI). The models assessed include traditional parametric approaches (ARIMAX, MLR), machine learning techniques (ANN, SVR, RFR), and advanced ensemble methods like XGBoost. The results highlight XGBoost as the most accurate model, consistently delivering the lowest error metrics, including RMSE and MAE, across all vegetation indices. Specifically, XGBoost achieved the best performance with LAI showing RMSE of 86.657, MAE of 58.324, sMAPE of 14.354, MASE of 1.001, and QL of 29.162 respectively. They exhibited lower error metrics, as compare to the statistical and ML models underscoring their effectiveness and potential in tobacco yield prediction. This study highlights the significant role of remote sensing technology in capturing crop development patterns and accurately forecasting tobacco yield, thereby offering valuable insights for agricultural planning and decision-making. The study also addresses challenges such as data quality and model generalization, providing a comprehensive view of the research impact and future directions.

Dependence of Photosynthetic Activity and Yield of Plum Varieties on the Use of Non-Root Fertilizing in the Arid Zone of the Northern Caspian Sea

In 2021–2023, the effect of non-root fertilizer application on photosynthetic activity and yield of plum varieties in the arid zone of the Northern Caspian Sea was studied. It was found that the leaf surface area on average during the growing season in the variant of the combined use of Aquarin + Ultramag boron + + Ultramag calcium exceeded the control by 50%. An increase in photosynthetic potential was noted when treated with Aquarin and Master fertilizers by 25.0 and 42%, respectively. The maximum increase in yield (12.8 t/ha) was obtained during leaf processing in the variant of the combined use of Aquarin + + Ultramag boron + Ultramag calcium preparations, which exceeded the control by 34.7%. It should be noted that the best responsiveness to non-root top dressing was distinguished by the Gigantic variety, whose yield was 13.2 t/ha, which was 39% more than the control.